I never feed my fish hot dogs. Their meat and fat is of wrong origin, they have too many chemicals and bio-chemicals, fillers, additives, preservatives (toxins really... just in a small dose), salt, often spices/seasoning, and other ingredients I know nothing of.
Sure, most predatory fish may snatch a mammal, bird, large land insect, etc. once in a while but those are "natural" and rather rare meals for most. Yes, some fish make a staple of terrestrial foods but those are few. Certainly not catfish.
Anyhow, the right idea, I think, is to mimic what the fish eat in the wild to the best of everyone's ability. The diet for almost all my fish consists of pellets (mostly Zeigler sinking catfish pellets) and small fish I catch in the Gulf of Mexico, rarely from f/water, plus some rarely fed (expensive) foods for diversification. I freeze all I catch to kill parasites.
Also, as I mentioned many times, it pays to explore local fish-selling joints - stand-alones and markets, etc. Even fish sections of supermarkets - may make friends with a manager and help them clean up and get rid of scraps and "waste" for a good cause. When we were in Rochester, NY I found a small Korean-run local fish shop, where I was getting substandard fish for $0.5/lb. There was nothing wrong with that fish, called "Spot". That was my staple for predators for a long time.
I don't see why go hot-dog route at the moment. Yes, many use them. I have lots of respect for Oddball and for Wednesday13, who is running like 30 tanks and ponds. We are all learning together in part by informing our friends and colleagues here of our successes and failures, short-term and, what is especially hard to come by, long-term ones.
I am with Oddball on this but am open to new knowledge. Suffice to say, I have never met someone I consider a high-level expert, scientist, respectable LFS keeper or a Public Aquarium worker, etc. who'd say foods of terrestrial origin are ok to use in large % for predatory fishes.
